COMBINED CYTOLOGICAL AND HISTOLOGICAL ANALYSIS IMPROVES THE DIAGNOSTIC ACCURACY OF ENDOSCOPIC ULTRASOUND-GUIDED FINE NEEDLE BIOPSY COMPARED TO HISTOLOGICAL EVALUATION ALONE IN ABDOMINAL SOLID MASSES

Background: The combination of cytologic smears and cell block preparation for histological analysis has been shown to increase the diagnostic accuracy of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) compared to histological evaluation alone in the absence of Rapid-onsite Evaluation (ROSE). Recent studies suggest that EUS-fine needle biopsy (EUS-FNB) with histological examination provides excellent results without ROSE. However, data on the diagnostic accuracy of combined cytological and histological analysis compared to histology alone obtained from EUS-FNB are scarce.
Method: A retrospective review of patients with intra-abdominal masses who underwent EUS-FNB in the absence of ROSE with both cytological and histological slides available. Specimens were reviewed by an experienced GI cytopathologist blinded to clinical data, prior results, and final diagnosis. The final diagnosis was established by surgical specimen, EUS-FNB results, or clinical course of at least 12 months follow-up. The primary outcome was to compare the diagnostic performance of combined conventional cytological and histological analysis with histological assessment alone.
Results: 134 cases were included in the study. The mean age was 62.56 years old. One hundred twenty had neoplasms, and 14 had benign disease. Common diagnoses included pancreatic cancer (n = 62) and mesenchymal tumor (n = 15). The mean size was 3.85 cm; the most common site was the pancreatic head (n = 55). Overall, histology alone provided an area under the receiver operating characteristic (AUROC) curve of 0.83, and cytology alone provided an AUROC of 0.82 (Table 1). The combination of cytological and histological analysis significantly increased sensitivity (p = 0.01) and the AUROC from 0.83 to 0.87 (p=0.003) compared to histology alone (Table 2). Subgroup analysis with pancreatic lesions was performed, and similar effects were identified. Histology alone provided an AUROC of 0.83, whereas the combination of cytology and histology provided an AUROC of 0.088 (p=0.016). The sensitivity also increased significantly (p = 0.04) (Table 2).
Conclusion: Combining cytology and histology from EUS-FNB yielded a higher diagnostic performance when compared to histology alone. This finding favors the practice of sending specimens for both cytology and histology.